1. Field of the Invention
The present invention relates to a magnetic element used for various electric products such as a power supply section of a computer, and particularly to a plate member to form the magnetic element, the magnetic element using the plate member, and a manufacturing method of the magnetic element.
2. Description of the Related Art
Among magnetic elements such as an inductor, there exists one formed by press-molding and subsequently thermosetting a paste being a mixture of magnetic powders, resin, and the like. The magnetic element of such a type is formed to have the same shape as of a hollow section (cavity) formed by facing a core and a drag to each other. As an example magnetic element of this type, there is one disclosed in Japanese Patent Application Laid-Open No. 2002-203731 (refer to FIGS. 3 and 4, Paragraph No. 0027 and so forth) (hereinafter “Patent document 1”).
According to the art disclosed in Patent document 1, in order to manufacture a magnetic element, first, a paste having a high-hardness portion and a low-hardness portion is formed. The high-hardness portion is provided on a rear surface portion of the paste and the low-hardness portion is provided on an upper surface side while it is adjacent to the rear surface portion. The low-hardness portion includes an outer leg portion and a middle leg portion. The paste is disposed inside a mold, and an exterior section is constituted by a press-molding of the paste in which the middle leg portion and outer leg portion are collapsed.
In the magnetic element manufacturing method disclosed in Patent document 1, no description is given as of an electric terminal to which an end of a winding wire is connected, therefore, here, a supplemental description will be given for the parts on the basis of the conventional arts. In order to form the terminal, a plate member provided with a frame portion and a protruding portion inwardly protruding from the frame portion is fabricated by die-cutting a metal plate. Then, powder pressing of a paste (granulated powders) is performed while the protruding portion is still with the frame member and, after that, the protruding portion is cut from the plate member. With these steps, in the course of manufacturing the magnetic element, it is possible to ensure to hold/position the terminal with respect to the magnetic element.
Meanwhile, a case where a change is made to an inductance value of the magnetic element upon a client request or so forth can be seen frequently. In that case, what needed to do is simply to change a winding number of a coil of the magnetic element. However, in the case of the magnetic element disclosed in Patent document 1 above, when changing the winding number of the coil, the shape of the mold to fabricate the terminal composing the magnetic element should be changed together. In other words, when changing the winding number of the coil, sometimes, there arises a case where the setting position of the terminal connecting the end of the winding wire should be changed together. In that case, the position of the protruding portion with respect to the frame portion is changed, so that the shape of the mold to fabricate the plate member should be changed together.
Here, as in the configuration disclosed in Patent document 1, when a round wire is adopted as a winding wire composing the coil, fluctuation in the inductance value for a tern is small, so that, in many cases, the change of the setting position of the terminal is not required. However, in recent years, along with demands for downsizing the magnetic elements, an approach, in which heat generation is suppressed by lowering resistance on the back of larger electric current, is increasingly adopted. In order to meet these demands, in the magnetic elements, a flat wire is used and a configuration, in which the winding number of the flat wire is small, is adopted, in many cases. In the configuration, the winding number is small, so that the fluctuation in the inductance value for a tern of the winding wire increases. In the magnetic element of such a configuration, when changing the inductance value, the positional relationship of a pair of ends of the coil changes frequently, and, in that case, the setting position change is required for the terminal together.
However, as described above, in the case where the plate member having the terminal is fabricated by die-cutting the metal plate, a change of the setting position of the terminal requires a shape change of the mold for the die-cut together. However, the change of the mold to form the plate member for each case in response to each customer request increases the production cost of the magnetic elements, being a problem.